Abstract
Ultrastructural changes in the glomerular basement membrane (GBM) of 415 samples from 344 patients with IgA nephritis, were examined for potential relationship to hematuria. The GBM showed various alterations: splitting, thinning, membranolysis with swelling of the lamina rara externa and interna, forming of small projections, and rupture. These lesions were present in 48% of IgA nephritis and in 16% of the controls. In the IgA nephritis group, the patients with hemispherical mesangial dense deposits had the highest rate (60%) of capillary wall abnormalities. Such lesions were more frequent in patients biopsied during severe hematuria (80%) than in those biopsied without hematuria (33%), (p < 0.01). It is assumed that the ultrastructural abnormalities of GBM may contribute to the clinical evidence of severe hematuria.